Toronto SEO
All HTTP status codes
4xx Client Error
RFC 8470

425 Too Early

The server is unwilling to risk processing a request that might be replayed.

What it means

HTTP 425 Too Early indicates that the server is unwilling to process a request that might be replayed, used in TLS 1.3 0-RTT (early data) scenarios where replay attacks are possible.

When it's used

TLS 1.3 connections where the request was sent in 0-RTT early data and the server wants to require a full handshake first.

Common causes
  • Client sent non-idempotent request in TLS 1.3 0-RTT data
  • Replay-vulnerable endpoint hit during early data
How to fix it
  • Retry the request without 0-RTT (use full handshake)
  • Restrict 0-RTT to idempotent operations only on the client side
  • Disable 0-RTT for sensitive endpoints
Example response
HTTP/1.1 425 Too Early
Connection: close
SEO impact

Should never affect crawlers.